This section: https://pamyat-naroda.ru/ops/ tracks the movement of Fronts, Armies, Corps, Division, Regiments and Commanders on the Eastern front throughout the course of the war. This appears to be based on Army reports. You can even see their positions on historical Soviet topographical maps. In some cases source documents are provided (some are translatable but some are just images). There are also diagrams of major attacks from a strategic perspective.

I wish there was something like this in English for the other Allies. If there was I guess we would have to pay for it.

FGM Corporal

When it comes to the battle of the Khorsun-Cherkassy Pocket in January and February 1944 the Soviet info was a bit too exaggerated according to some historians. But that was of course a couple of months before the Summer so the Soviets maybe had changed to the better by then.

FGM Colour Sergeant

I have been reading a lot about Stalingrad, mostly Glantz and Marks. Marks compares both sides, particularly around the Barrikady factory, according to his book the Soviets appeared to be exaggerating. In his latest Panzkrieg, from a German perspective the Soviets are taking huge tank losses during Case Blue, almost unbelievable.

Have not got as far as 44 but I did just pick up The Korsun Pocket by Zettling and Frankson on Kindle for a few USD. Have you got any other recommendations I can add to my list?